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<head>
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    <title>Document</title>
    <style>
        main {
            transition: .6s filter;
        }

        main.de-emphasized {
            filter: blur(5px);
        }
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</head>

<body>
    <main>Bacon Ipsum dolor sit amet...</main>
    <dialog>
        O HAI, I'm a dialog. Click on me to dismiss.
    </dialog>
</body>

</html>